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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Copyright (C) 2007 The Guava Authors<a name="line.2"></a>
<span class="sourceLineNo">003</span> *<a name="line.3"></a>
<span class="sourceLineNo">004</span> * Licensed under the Apache License, Version 2.0 (the "License");<a name="line.4"></a>
<span class="sourceLineNo">005</span> * you may not use this file except in compliance with the License.<a name="line.5"></a>
<span class="sourceLineNo">006</span> * You may obtain a copy of the License at<a name="line.6"></a>
<span class="sourceLineNo">007</span> *<a name="line.7"></a>
<span class="sourceLineNo">008</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * Unless required by applicable law or agreed to in writing, software<a name="line.10"></a>
<span class="sourceLineNo">011</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.11"></a>
<span class="sourceLineNo">012</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.12"></a>
<span class="sourceLineNo">013</span> * See the License for the specific language governing permissions and<a name="line.13"></a>
<span class="sourceLineNo">014</span> * limitations under the License.<a name="line.14"></a>
<span class="sourceLineNo">015</span> */<a name="line.15"></a>
<span class="sourceLineNo">016</span><a name="line.16"></a>
<span class="sourceLineNo">017</span>package com.google.common.collect;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import com.google.common.annotations.Beta;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import com.google.common.annotations.GwtCompatible;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import com.google.common.base.Objects;<a name="line.21"></a>
<span class="sourceLineNo">022</span><a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.Map;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.Map.Entry;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>import javax.annotation.Nullable;<a name="line.26"></a>
<span class="sourceLineNo">027</span><a name="line.27"></a>
<span class="sourceLineNo">028</span>/**<a name="line.28"></a>
<span class="sourceLineNo">029</span> * A map entry which forwards all its method calls to another map entry.<a name="line.29"></a>
<span class="sourceLineNo">030</span> * Subclasses should override one or more methods to modify the behavior of the<a name="line.30"></a>
<span class="sourceLineNo">031</span> * backing map entry as desired per the &lt;a<a name="line.31"></a>
<span class="sourceLineNo">032</span> * href="http://en.wikipedia.org/wiki/Decorator_pattern"&gt;decorator pattern&lt;/a&gt;.<a name="line.32"></a>
<span class="sourceLineNo">033</span> *<a name="line.33"></a>
<span class="sourceLineNo">034</span> * &lt;p&gt;&lt;i&gt;Warning:&lt;/i&gt; The methods of {@code ForwardingMapEntry} forward<a name="line.34"></a>
<span class="sourceLineNo">035</span> * &lt;i&gt;indiscriminately&lt;/i&gt; to the methods of the delegate. For example,<a name="line.35"></a>
<span class="sourceLineNo">036</span> * overriding {@link #getValue} alone &lt;i&gt;will not&lt;/i&gt; change the behavior of<a name="line.36"></a>
<span class="sourceLineNo">037</span> * {@link #equals}, which can lead to unexpected behavior. In this case, you<a name="line.37"></a>
<span class="sourceLineNo">038</span> * should override {@code equals} as well, either providing your own<a name="line.38"></a>
<span class="sourceLineNo">039</span> * implementation, or delegating to the provided {@code standardEquals} method.<a name="line.39"></a>
<span class="sourceLineNo">040</span> *<a name="line.40"></a>
<span class="sourceLineNo">041</span> * &lt;p&gt;Each of the {@code standard} methods, where appropriate, use {@link<a name="line.41"></a>
<span class="sourceLineNo">042</span> * Objects#equal} to test equality for both keys and values. This may not be<a name="line.42"></a>
<span class="sourceLineNo">043</span> * the desired behavior for map implementations that use non-standard notions of<a name="line.43"></a>
<span class="sourceLineNo">044</span> * key equality, such as the entry of a {@code SortedMap} whose comparator is<a name="line.44"></a>
<span class="sourceLineNo">045</span> * not consistent with {@code equals}.<a name="line.45"></a>
<span class="sourceLineNo">046</span> *<a name="line.46"></a>
<span class="sourceLineNo">047</span> * &lt;p&gt;The {@code standard} methods are not guaranteed to be thread-safe, even<a name="line.47"></a>
<span class="sourceLineNo">048</span> * when all of the methods that they depend on are thread-safe.<a name="line.48"></a>
<span class="sourceLineNo">049</span> *<a name="line.49"></a>
<span class="sourceLineNo">050</span> * @author Mike Bostock<a name="line.50"></a>
<span class="sourceLineNo">051</span> * @author Louis Wasserman<a name="line.51"></a>
<span class="sourceLineNo">052</span> * @since 2.0 (imported from Google Collections Library)<a name="line.52"></a>
<span class="sourceLineNo">053</span> */<a name="line.53"></a>
<span class="sourceLineNo">054</span>@GwtCompatible<a name="line.54"></a>
<span class="sourceLineNo">055</span>public abstract class ForwardingMapEntry&lt;K, V&gt;<a name="line.55"></a>
<span class="sourceLineNo">056</span>    extends ForwardingObject implements Map.Entry&lt;K, V&gt; {<a name="line.56"></a>
<span class="sourceLineNo">057</span>  // TODO(user): identify places where thread safety is actually lost<a name="line.57"></a>
<span class="sourceLineNo">058</span><a name="line.58"></a>
<span class="sourceLineNo">059</span>  /** Constructor for use by subclasses. */<a name="line.59"></a>
<span class="sourceLineNo">060</span>  protected ForwardingMapEntry() {}<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span>  @Override protected abstract Map.Entry&lt;K, V&gt; delegate();<a name="line.62"></a>
<span class="sourceLineNo">063</span><a name="line.63"></a>
<span class="sourceLineNo">064</span>  @Override<a name="line.64"></a>
<span class="sourceLineNo">065</span>  public K getKey() {<a name="line.65"></a>
<span class="sourceLineNo">066</span>    return delegate().getKey();<a name="line.66"></a>
<span class="sourceLineNo">067</span>  }<a name="line.67"></a>
<span class="sourceLineNo">068</span><a name="line.68"></a>
<span class="sourceLineNo">069</span>  @Override<a name="line.69"></a>
<span class="sourceLineNo">070</span>  public V getValue() {<a name="line.70"></a>
<span class="sourceLineNo">071</span>    return delegate().getValue();<a name="line.71"></a>
<span class="sourceLineNo">072</span>  }<a name="line.72"></a>
<span class="sourceLineNo">073</span><a name="line.73"></a>
<span class="sourceLineNo">074</span>  @Override<a name="line.74"></a>
<span class="sourceLineNo">075</span>  public V setValue(V value) {<a name="line.75"></a>
<span class="sourceLineNo">076</span>    return delegate().setValue(value);<a name="line.76"></a>
<span class="sourceLineNo">077</span>  }<a name="line.77"></a>
<span class="sourceLineNo">078</span><a name="line.78"></a>
<span class="sourceLineNo">079</span>  @Override public boolean equals(@Nullable Object object) {<a name="line.79"></a>
<span class="sourceLineNo">080</span>    return delegate().equals(object);<a name="line.80"></a>
<span class="sourceLineNo">081</span>  }<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>
<span class="sourceLineNo">083</span>  @Override public int hashCode() {<a name="line.83"></a>
<span class="sourceLineNo">084</span>    return delegate().hashCode();<a name="line.84"></a>
<span class="sourceLineNo">085</span>  }<a name="line.85"></a>
<span class="sourceLineNo">086</span><a name="line.86"></a>
<span class="sourceLineNo">087</span>  /**<a name="line.87"></a>
<span class="sourceLineNo">088</span>   * A sensible definition of {@link #equals(Object)} in terms of {@link<a name="line.88"></a>
<span class="sourceLineNo">089</span>   * #getKey()} and {@link #getValue()}. If you override either of these<a name="line.89"></a>
<span class="sourceLineNo">090</span>   * methods, you may wish to override {@link #equals(Object)} to forward to<a name="line.90"></a>
<span class="sourceLineNo">091</span>   * this implementation.<a name="line.91"></a>
<span class="sourceLineNo">092</span>   *<a name="line.92"></a>
<span class="sourceLineNo">093</span>   * @since 7.0<a name="line.93"></a>
<span class="sourceLineNo">094</span>   */<a name="line.94"></a>
<span class="sourceLineNo">095</span>  @Beta protected boolean standardEquals(@Nullable Object object) {<a name="line.95"></a>
<span class="sourceLineNo">096</span>    if (object instanceof Entry) {<a name="line.96"></a>
<span class="sourceLineNo">097</span>      Entry&lt;?, ?&gt; that = (Entry&lt;?, ?&gt;) object;<a name="line.97"></a>
<span class="sourceLineNo">098</span>      return Objects.equal(this.getKey(), that.getKey())<a name="line.98"></a>
<span class="sourceLineNo">099</span>          &amp;&amp; Objects.equal(this.getValue(), that.getValue());<a name="line.99"></a>
<span class="sourceLineNo">100</span>    }<a name="line.100"></a>
<span class="sourceLineNo">101</span>    return false;<a name="line.101"></a>
<span class="sourceLineNo">102</span>  }<a name="line.102"></a>
<span class="sourceLineNo">103</span><a name="line.103"></a>
<span class="sourceLineNo">104</span>  /**<a name="line.104"></a>
<span class="sourceLineNo">105</span>   * A sensible definition of {@link #hashCode()} in terms of {@link #getKey()}<a name="line.105"></a>
<span class="sourceLineNo">106</span>   * and {@link #getValue()}. If you override either of these methods, you may<a name="line.106"></a>
<span class="sourceLineNo">107</span>   * wish to override {@link #hashCode()} to forward to this implementation.<a name="line.107"></a>
<span class="sourceLineNo">108</span>   *<a name="line.108"></a>
<span class="sourceLineNo">109</span>   * @since 7.0<a name="line.109"></a>
<span class="sourceLineNo">110</span>   */<a name="line.110"></a>
<span class="sourceLineNo">111</span>  @Beta protected int standardHashCode() {<a name="line.111"></a>
<span class="sourceLineNo">112</span>    K k = getKey();<a name="line.112"></a>
<span class="sourceLineNo">113</span>    V v = getValue();<a name="line.113"></a>
<span class="sourceLineNo">114</span>    return ((k == null) ? 0 : k.hashCode()) ^ ((v == null) ? 0 : v.hashCode());<a name="line.114"></a>
<span class="sourceLineNo">115</span>  }<a name="line.115"></a>
<span class="sourceLineNo">116</span><a name="line.116"></a>
<span class="sourceLineNo">117</span>  /**<a name="line.117"></a>
<span class="sourceLineNo">118</span>   * A sensible definition of {@link #toString} in terms of {@link<a name="line.118"></a>
<span class="sourceLineNo">119</span>   * #getKey} and {@link #getValue}. If you override either of these<a name="line.119"></a>
<span class="sourceLineNo">120</span>   * methods, you may wish to override {@link #equals} to forward to this<a name="line.120"></a>
<span class="sourceLineNo">121</span>   * implementation.<a name="line.121"></a>
<span class="sourceLineNo">122</span>   *<a name="line.122"></a>
<span class="sourceLineNo">123</span>   * @since 7.0<a name="line.123"></a>
<span class="sourceLineNo">124</span>   */<a name="line.124"></a>
<span class="sourceLineNo">125</span>  @Beta protected String standardToString() {<a name="line.125"></a>
<span class="sourceLineNo">126</span>    return getKey() + "=" + getValue();<a name="line.126"></a>
<span class="sourceLineNo">127</span>  }<a name="line.127"></a>
<span class="sourceLineNo">128</span>}<a name="line.128"></a>




























































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